I received the Dyron 67mm adaptor from Scubacam Singapore (btw a superb shop). It was priced about $72 USD. Made of Delrin, it measures: OD: 70.0mmID: 44.3mmThickness: 11.5mmDepth of 67 mm side: 5.5mmDepth of 45mm side: 6.0mmWebsite claimed it comes with a teflon setscrew and safety strap. Nah. Only thing that prevents unscrewing when you dismount lenses is faith. And Loctite maybe. It does sit out of the way - no vignetting at 28mm focus with just the adaptors mounted.

Was concerned that the 10bar 67mm-AD convertor didn't screw into the Dyron all the way (see the gap),

until I mounted the macro lens and saw how the base protrudes just enough to exactly mate with the port glass surface on the housing.

All seems to work on dry land, although I may:1) loctite the Dyron to the housing, and the 10bar to the Dyron, and2) put a safety strap on the Inon wide angle, because the bayonet attachment seems a little dodgy, and I could see it maybe wiggling loose. Would sink like a stone.

Does Loctite work underwater? Alternatively I may drill some tiny holes and fix a coupla setscrews. We'll see how it works in the coming weeks.

Regarding Loctite and plastic - I spoke with the local Loctite rep who recommended Loctite 406. It is safe for all plastics, but since it is low-viscosity cyanoacrylate (basically Superglue), it is more of an adhesive than a threadlocker. What I ended up doing was:

- put a drop on the male threaded part and let it seep into the threads- let it dry - important if you ever want to take it apart- assemble the parts

The gob on the threads creates enough friction to make disassembly strenuous but possible. Now I have to see how it holds up under seawater immersion! At least the adaptor shouldn't unscrew with a 1/4 turn of the bayonet mount lens.

It has several advantages, perhaps. One is that it is about 1/3 the price of the FIX28AD adapter. Another is the direct, one piece threaded on design rather than three pieces and perhaps as a result more compact. Third, at least initially, reports were that it would have a nylon lock screw to engage the flats in the FIX90 port barrel. And, well, perhaps function better for the AD lenses since the FIX28AD mount was intended for 28AD bayonet lenses, not AD bayonet lenses. There was also hope that it would be anodized aluminum.

So, it appears it is resin or nylon construction and no lock screw but it does appear to be nicely made.

The idea for me to use the 67mm adapters and my DIY or the 10Bar AD to 67mm adapter is that it would be possible to mount a range of AD/28AD and threaded lenses without buying all three FIX adapters.

This new 10Bar, FIX90 port adapter from 10Bar plus their AD adapter seem to be cost effective and functional way to mount several different lenses.